package com.yxy.search;

import java.io.*;
import java.util.Date;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.*;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

public class SearchFiles
{

    private SearchFiles()
    {
    }

    public static void main(String args[])
        throws Exception
    {
        String usage = "Usage:\tjava org.apache.lucene.demo.SearchFiles [-index dir] [-field f] [-repeat n] [-queries file] [-query string] [-raw] [-paging hitsPerPage]\n\nSee http://lucene.apache.org/core/4_1_0/demo/ for details.";
        if(args.length > 0 && ("-h".equals(args[0]) || "-help".equals(args[0])))
        {
            System.out.println(usage);
            System.exit(0);
        }
        String index = "index";
        String field = "contents";
        String queries = null;
        int repeat = 0;
        boolean raw = false;
        String queryString = null;
        int hitsPerPage = 10;
        for(int i = 0; i < args.length; i++)
        {
            if("-index".equals(args[i]))
            {
                index = args[i + 1];
                i++;
                continue;
            }
            if("-field".equals(args[i]))
            {
                field = args[i + 1];
                i++;
                continue;
            }
            if("-queries".equals(args[i]))
            {
                queries = args[i + 1];
                i++;
                continue;
            }
            if("-query".equals(args[i]))
            {
                queryString = args[i + 1];
                i++;
                continue;
            }
            if("-repeat".equals(args[i]))
            {
                repeat = Integer.parseInt(args[i + 1]);
                i++;
                continue;
            }
            if("-raw".equals(args[i]))
            {
                raw = true;
                continue;
            }
            if(!"-paging".equals(args[i]))
                continue;
            hitsPerPage = Integer.parseInt(args[i + 1]);
            if(hitsPerPage <= 0)
            {
                System.err.println("There must be at least 1 hit per page.");
                System.exit(1);
            }
            i++;
        }

        IndexReader reader = DirectoryReader.open(FSDirectory.open(new File(index)));
        IndexSearcher searcher = new IndexSearcher(reader);
        Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_46);
        BufferedReader in = null;
        if(queries != null)
            in = new BufferedReader(new InputStreamReader(new FileInputStream(queries), "UTF-8"));
        else
            in = new BufferedReader(new InputStreamReader(System.in, "UTF-8"));
        QueryParser parser = new QueryParser(Version.LUCENE_46, field, analyzer);
        do
        {
            if(queries == null && queryString == null)
                System.out.println("Enter query: ");
            String line = queryString == null ? in.readLine() : queryString;
            if(line == null || line.length() == -1)
                break;
            line = line.trim();
            if(line.length() == 0)
                break;
            Query query = parser.parse(line);
            System.out.println((new StringBuilder()).append("Searching for: ").append(query.toString(field)).toString());
            if(repeat > 0)
            {
                Date start = new Date();
                for(int i = 0; i < repeat; i++)
                    searcher.search(query, null, 100);

                Date end = new Date();
                System.out.println((new StringBuilder()).append("Time: ").append(end.getTime() - start.getTime()).append("ms").toString());
            }
            doPagingSearch(in, searcher, query, hitsPerPage, raw, queries == null && queryString == null);
        } while(queryString == null);
        reader.close();
    }

    /**
     * This demonstrates a typical paging search scenario,
     *  where the search engine presents pages of size n to the user. 
     *  The user can then go to the next page if interested in the next hits. 
     *  When the query is executed for the first time, then only enough results 
     *  are collected to fill 5 result pages. If the user wants to page beyond this limit, 
     * then the query is executed another time and all hits are collected
     * @param in
     * @param searcher
     * @param query
     * @param hitsPerPage
     * @param raw
     * @param interactive
     * @throws IOException
     */
    public static void doPagingSearch(BufferedReader in, IndexSearcher searcher, Query query, int hitsPerPage, boolean raw, boolean interactive)
        throws IOException
    {
        TopDocs results = searcher.search(query, 5 * hitsPerPage);
        ScoreDoc hits[] = results.scoreDocs;
        int numTotalHits = results.totalHits;
        System.out.println((new StringBuilder()).append(numTotalHits).append(" total matching documents").toString());
        int start = 0;
        int end = Math.min(numTotalHits, hitsPerPage);
        do
        {
            if(end > hits.length)
            {
                System.out.println((new StringBuilder()).append("Only results 1 - ").append(hits.length).append(" of ").append(numTotalHits).append(" total matching documents collected.").toString());
                System.out.println("Collect more (y/n) ?");
                String line = in.readLine();
                if(line.length() == 0 || line.charAt(0) == 'n')
                    break;
                hits = searcher.search(query, numTotalHits).scoreDocs;
            }
            end = Math.min(hits.length, start + hitsPerPage);
            for(int i = start; i < end; i++)
            {
                if(raw)
                {
                    System.out.println((new StringBuilder()).append("doc=").append(hits[i].doc).append(" score=").append(hits[i].score).toString());
                    continue;
                }
                Document doc = searcher.doc(hits[i].doc);
                String path = doc.get("path");
                if(path != null)
                {
                    System.out.println((new StringBuilder()).append(i + 1).append(". ").append(path).toString());
                    String title = doc.get("title");
                    if(title != null)
                        System.out.println((new StringBuilder()).append("   Title: ").append(doc.get("title")).toString());
                } else
                {
                    System.out.println((new StringBuilder()).append(i + 1).append(". ").append("No path for this document").toString());
                }
            }

            if(!interactive || end == 0)
                break;
            if(numTotalHits < end)
                continue;
            boolean quit = false;
            do
            {
                System.out.print("Press ");
                if(start - hitsPerPage >= 0)
                    System.out.print("(p)revious page, ");
                if(start + hitsPerPage < numTotalHits)
                    System.out.print("(n)ext page, ");
                System.out.println("(q)uit or enter number to jump to a page.");
                String line = in.readLine();
                if(line.length() == 0 || line.charAt(0) == 'q')
                {
                    quit = true;
                    break;
                }
                if(line.charAt(0) == 'p')
                {
                    start = Math.max(0, start - hitsPerPage);
                    break;
                }
                if(line.charAt(0) == 'n')
                {
                    if(start + hitsPerPage < numTotalHits)
                        start += hitsPerPage;
                    break;
                }
                int page = Integer.parseInt(line);
                if((page - 1) * hitsPerPage < numTotalHits)
                {
                    start = (page - 1) * hitsPerPage;
                    break;
                }
                System.out.println("No such page");
            } while(true);
            if(quit)
                break;
            end = Math.min(numTotalHits, start + hitsPerPage);
        } while(true);
    }
}